Field of the Invention
The present invention relates to a control apparatus which is capable of performing focus control.
Description of the Related Art
Previously, a focus detection method by using a contrast detection method and a phase-difference detection method has been known. The contrast detection method and the phase-difference detection method are focus detection methods often used in a video camera and a digital still camera. Furthermore, a configuration in which focus detection is performed by using an image pickup element as a focus detection sensor has been known. In this focus detection method, a focus detection result may contain an error caused by various aberrations of an optical system, and a method of reducing the error has been proposed.
Japanese Patent No. 5087077 discloses a method of calculating a correction value to correct a focus detection result (focus detection error) depending on an evaluation frequency (evaluation band) of focus detection signals. This focus detection error occurs depending on the evaluation band of the focus detection signals used in performing focus detection. In Japanese Patent No. 5087077, the evaluation band of the focus detection signals is specified as a focus detection error, and the focus detection result is corrected by using the correction value appropriate for the evaluation band.
By the way, the focus detection error originally corresponds to a difference between a focus state in which a user can feel that a captured image is in the best focus state and a focus state obtained from the focus detection result. However, Japanese Patent No. 5087077 does not disclose a focus state of a captured image. Accordingly, in the configuration of Japanese Patent No. 5087077, the focus detection error cannot be sufficiently corrected.